Typically, disc brake systems include a support bracket, two or more brake pads, a caliper, and a rotor. The two or more brake pads are mounted and located adjacent to the support bracket so that the brake pads move axially, along the rotor axis, a piston bore axis, or both, towards and away from the rotor. The disc brake system may include a pad clip that attaches to the brake system between the support bracket and the brake pads so that the brake pads are retained within the brake system and move along the pad clip. The disc brake system may include one or more springs to assist in retracting the brake pads away from a rotor when the brakes are released, and the one or more springs may abut against or be secured to a portion of the support bracket. Examples of springs and pad retraction devices are disclosed in U.S. Pat. Nos. 8,376,092; 8,397,880; and 8,399,441; and U.S. Patent Application Publication No 2012/0222925 all of which are expressly incorporated herein by reference for all purposes.
One challenge faced by retraction springs is that the springs may allow a portion of the brake pads to tip slightly toward the rotor. For example, a retraction spring may contact a brake pad above or below a longitudinal center line of the brake pad. As the spring contacts the brake pad and assists the brake pad in retracting, force may not be adequately distributed along the brake pad so that the brake pad may not retract evenly. A portion of the brake pad (i.e., above or below a longitudinal center line) may tilt toward the rotor, which may result in incidental contact between the pad and rotor; causing uneven wear of the rotor, uneven wearing of the friction material of the brake pad, an increase in residual (brakes off) drag, and rattle noise.
There is a need for a retraction spring design that applies a consistent force to the brake pads throughout wearing of the brake pad; reduces or prevents pad tipping or rotation along a longitudinal axis of the brake pad; assists in providing an even brake pad retraction; reduces air gap; or a combination thereof.